Switch with automatic shutdown (CB21258E)

This circuit was found in Maxim documentation from the 1990s. The RC circuit determines the trigger time.

High Voltage Regulator (CB14323E)
The circuit shown was found in the National Semiconductor's Linear Applications Handbook of 1994....
Telephne Audio Interface (CB21269E)
This circuit from a Popular Electronics shows how to take the audio signal from a telephone line...
Capacitive discharge ignition (CB24182E)
This circuit is from a Radio Electronics from April 1972. The circuit uses power transistors of...